Our long range research goals are to understand the biogenesis, structure and function of the F1 Fo ATPase complex. This ubiquitous enzyme complex converts an electrochemical ion gradient into ATP and thus serves as the primary source of cellular energy for nearly all organisms. We propose to continue our examination of the mechanism of differential translation of the unc genes which specify the 8 polypeptides of the F1 Fo complex of E. coli. We will extend our mutagenic analysis of the F1 Fo polypeptides with a focus on the polypeptides of the Fo and their role in ion translocation. Of particular importance will be an exhaustive site-directed mutagenesis study of the a subunit of Fo which we feel is the key polypeptide for ion movement. We will also focus on the delta subunit of F1 since preliminary results indicate that this polypeptide may structurally and functionally couple F1 to Fo. It is our hope to initiate structural analysis of both the F1 and the Fo. We will try to induce two dimensional order in membranes by overproduction of the Fo complex. We will also try to crystallize the delta subunit and an alpha, beta, and gamma complex of F1. Lastly, we will study the comparative structure and function of the F1 Fo complexes from two bacteria, Propionigenium modestum and Vibrio alginolyticus, which couple a sodium gradient to ATP synthesis.